The present invention relates generally to the field of orthopedic medicine and more specifically to the design of an improved, low density medical bandage substrate, a medical bandage formed of a moisture-curable material, particularly a splint, and a medical bandaging product.
Medical bandages for use in the treatment of injuries, such as broken bones requiring immobilization of a body member, are generally formed from a strip of fabric or scrim material impregnated with a substance which hardens into a rigid structure after the strip has been wrapped around the body member. The hardening substance traditionally used in carrying out this procedure is plaster-of-paris.
Conventional practice has been to fabricate a cast or splint upon an injured limb by initially applying to the limb a protective covering of a cotton fabric or the like and then overwrapping the covering and limb with a woven cloth impregnated with plaster-of-paris which has been wetted by dipping in water immediately prior to application. This practice is still in widespread use but possesses several significant disadvantages. For example, the above-described application procedure is messy and time-consuming. Several components are required and considerable skill is necessary when applying. The hardened material is subject to deterioration during wear, is heavy and can cause odor and itching.
In order to alleviate the above-recited disadvantages of the conventional application procedure for plaster-of-paris casts and splints, unitary splinting materials have been devised and are disclosed in, for example, U.S. Pat. Nos. 3,900,024, 3,923,049, and 4,235,228. All of these patents describe a padding material with a plurality of layers of plaster-of-paris impregnated cloth. Such unitary splinting materials are not as messy and can be applied more quickly but still suffer from a number of disadvantages inherent in plaster-of-paris cast materials. All plaster-of-paris splints have a relatively low strength to weight ratio which results in a finished splint which is very heavy and bulky. Plaster-of-paris splints are slow to harden, requiring 24 to 72 hours to reach maximum strength. Since plaster-of-paris breaks down in water, bathing and showering are difficult.
An advance in the art of casting and splinting is disclosed in U.S. Pat. Nos. 4,411,262 and 4,502,479. The casting materials disclosed in these patents comprise a flexible fabric impregnated with a moisture-curing resin enclosed in a moisture-free, moisture-impervious package. Compared to plaster-of-paris, these products are extremely lightweight, have a very high strength to weight ratio and can be made relatively porous, permitting a flow of air through the splinting material. Prior art moisture-curing systems include a package within which is contained a plurality of layers of fabric, such as fiberglass, impregnated with a moisture-curing resin. No provision is made for re-closing the package, so that the entire material must be very quickly used after removal from the package since such moisture-curing resins will cure in a relatively short period of time due merely to contact with atmospheric moisture.
Further significant developments in the splinting area are disclosed in U.S. Pat. Nos. 4,770,299; 4,869,046; 4,899,738 and 5,003,970, owned by present applicant. Each of these patents discloses various roll-form, moisture-curable splint products that permit predetermined lengths of a medical bandage to be severed from a roll for use, while the remaining medical bandage is maintained in a soft, moisture-proof condition until ready for later use. These applications disclose the use of multiple layers of fiberglass fabric positioned in a synthetic, non-woven fabric protective layer for residing between the hardened substrate and the patient.
The present application presents and discloses further improvements addressed to presently-used products.
In particular, a double fabric substrate is disclosed having voids formed into the substrate to reduce the density of the substrate without impairing the ability of the substrate to adequately harden. The voids not only reduce the density of the substrate but form water ingress channels that permit faster, more even distribution of water into the structure of the substrate. The lower density of the substrate improves the weight ratio, the amount of water and moisture-curable resin required, improves water take-up and distribution characteristics, and provides for more even hardening of the bandage. In addition, the edges of the substrate may be formed in such a way as to be less rigid when cured, thereby improving comfort to the patient. The substrate is more formable and the lamination will not separate when wrapping around an angle, for example, heel or elbow.
The invention described in this application combine the advantages of both plaster-of-paris and moisture-curable resin systems while avoiding their respective disadvantages. This is accomplished by providing unitary splinting systems with improved strength and convenience. One such unitary system uses a moisture-curing resin together with a moisture-impervious package with means for resealing the package against entry of moisture after a desired length of bandaging product has been removed for use. In this manner, hardening of the bandaging product remaining in the moisture-impervious package is prevented thereby increasing the cost effectiveness of the system substantially. Another unitary system provides pre-cut lengths sealed against moisture intrusion until use.